Rheostat with centrifugal operator



May 24, 1949. R. A. FELBURG 2,470,768

RHEOSTAT WITH CENTRIFUGAL OPERATOR Filed April 2s, 194e 4 sheets-sheet 1 l l I E i N Vlm n u FN un un F 2 N n E N I g \l r2 -n- N m ROBERT A. FELBURG M dsawzzw F I G.|

STARTER May 24, 1949. R A FELBURG 2,470,768

RHEQSTAT WITH CENTRIFUGAL OPERATOR Filed April 23, 1946 4 Sheets-Sheet 2 ROBERT A. FELBURG May 24, 1949. R. A. FELBURG RHEOSTAT WITH CENTRIFUGAL OPERATOR 4 Sheets-Sheet 4 Filed April 23, 1946 :vllllrlillllfflralfal NQ@ mm. WN.

MEOFDV Dmmnm. 23232;)- m IIIHHH :alnuillliulllvllllllnllnvnnnllnllinl llnlflinulllilllul Patented May 24, 1949 iJNiTEo STATES rari-:Nr ortica RHEOSTAT WITH CEN TRIFUGAL OPERAT Robert A. Felburg, Newark, N. J. Application April 23, .1946, Serial No. .664,166

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lilly invention relates broadly .to control means ior electrical apparatus and more particularly to a centrifugal governing mechanism for rotating electrical apparatus.

This application is a continuation-ln-part of my application Serial No. 591,472, filed Septem- 'per 7, 1943, now Patent No. 2,399,218, issued April 30, 1946, for Aircraft landing gear.

One of the objects of my invention is to provide a construction of centrifugal operating control mechanism for rotating electrical apparatus.

Another object of my invention is to provide an arrangement of centrifugal weights associated with the rotary element of an electrical motor or generator for controlling an electrical contact system according to the speed of the motor or generator for correspondingly controlling the electrical circuit associated with the motor or generator.

Still another object of my invention is to provide a compact arrangement of an electrical circuit control element associated with an electrical motor or generator whichI may be variably controlled according to the speed of operation of the motor or generator for correspondingly controlling the electrical circuit associated with the motor or generator.

Still another object of my invention is to provide a compact arrangement of an electrical circuit control element associated with an electrical motor or generator which may be variably controlled according to the speed of operation of the motor or generator for correspondingly controlling the electrical circuit associated with the motor or generator.

Still another object of my invention is to provide an arrangement of. circuit control elements concentrically associated with the operating shaft of rotating electrical apparatus and which.

includes a calibrated resistance progressively tapped and controlled by centrifugal mechanism for associating the resistance in circuit with the rotating electrical apparatus as a starting resistance, as a constant speed governor, or as a starter governor combination in the control circuit of the apparatus. i

Other and further objects of my invention reside in the construction of a compactlyarranged centrifugally operated control mechanism for rotating electrical machinery in general, as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a vertical sectional view taken through an electric motor or generator equipped with the centriiugally operated electrically controllec mechanism of my invention; Fig. 2 is a transverse sectional view taken substantially on .line of Fig. i; Fig. 3 is a perspective view ci a fragmentary portion of the variable electrical contact system employed in the control system oi my invention; Fig. 4 is an enlarged fragmentary transverse sectional view taken through the contact system employed in the control mechanism of my invention; Fig. 5 is Va schematic View illustrating the calibrated resistance which is variably included in circuit with the rotating equipment during starting of the equipment; Fig. 6 is a schematic view illustrating the arrangement of resistance which is provided for the mechanism when used as a constant speed governor in rotatable electrical apparatus; Fig. 7 is a schematic view of the rotating electrical apparatus for oper-ation as a starter governor combination; Fig. 8 is a schematic view illustrating the position of the control resistance in circuit With the rotating electrical apparatus; Fig. 9 is a longitudinal cross sectional View ytaken through a modified form of control switch mechanism applied to an electric motor, the governing mechanism being shown in normal operating position and below an excessive speed condition for maintaining the contacts of the switch mechanism closed; Fig. l0 is a transverse sectional view taken on line l0 |0 of Fig. 9; and Fig. 11 is a fragmentary sectional view showing the contacts of the switch mechanism separated under conditions of excessive speed oi' the governing mechanism.

Referring to the drawings in more detail, reference character indicates a rotating electrical apparatus such as Van electric motor or an electric generator having a shaft 3l which extends through a Itubular member 2 projecting from the apparatus l and beyond the housing 53 for connection to any desired work application in the case of a motor or .to a prime mover in the case on a generator. Ball races 3 are located at spaced intervals for mutually supporting the shaft 3l and tubular member 2. Tubular member 2 provides .a bearing surface over which the tubular member 5 is free to longitudinally slide. 'Ihe tubular member 4 is provided with a flange 5 at the end thereof which is peripherally screwthreaded at 5a for receiving coactng internal screw threads on coupling member -B which terminates in a flanged wall 1 having a central aperture la therein for the passage of the slidably adjust-able sleeve 8|. The slidably adjustable sleeve 8| terminates in an annular flange 84 the resistance which is associated with which establishes low friction coupling relation with the coupling member '6 through ball bearing recess indicated at 8 and 9. Thus, flange 84 may be rotatably driven at high speed and dis- -placed longitudinally along shaft 3| proportional to speed for imparting itranslatory movement of the brush contact I insulatingly and resillently supported through insulator II and spring member I2 on slidable tubular member 4.

The electrical brush member I0 slides over a multiplicity of longitudinally arranged contact members represented generally at I4, suspended .by a channel member I4a depending from the coll support I5. The contact members I4 are suspended in a row longitudinally of the annular coil-supporting frame I5 which compactly surrounds thte slidable tubular member 4, the tubular member 2 and the rotatable shaft 3I. The annular coil support I5 is wound with resistance wire represented generally at I6 and which is provided with a multiplicity of progressive taps, which I have represented variously in Figs. 1-7 as graduated from 0-20 depending upon the type of control to be impressed upon the circuit through the apparatus.

The position of the brush or movable contact I0 is controlled by the movement of the centrifugal weights 13 and 14 attached to arms 1I and 12, respectively, and pivotally secured at 69 and 10 to the sleeve 61, which sleeve is set in a selected position on rotatable shaft 3| by means of set screw 63. The arms 1I and 12 connect through links 11 and 18 pivoted at 15 and 16 to arms 1| and 12, respectively, at one end, and pivoted at 19 and 80 to sleeve 8l at the other end. Spring members 2l and 22 are associated with each of the pivotal connections and 16, respectively, for continuously urging the governor arms 1I and 12 to a position relatively compressed or flush with the shaft 3| when the mechanism is at rest. The centrifugal weights 12 and 14, when spun around by rotation of shaft 3|, overcomes the action of springs 2| and 22 and tend to slide the sleeve 8| to the right in viewing Fig. 1, thereby shifting brush I0 along the'row of contacts I4. In order to control the movement of sleeve 8|, in the case of the starter and starter-governer combination, I provide a spring member 23 mounted on shaft 3| immediately below recess 24 ln shaft 3| and adjacent a recess 25 into which spring member 23 is adapted to be compressed or displaced. The spring has a contour which slopes gradually, enabling the shaped projection 82, which is carried by the slidable sleeve 8|, to readily travel over the spring when the shaft 3| is accelerating. I

However, when the shaft 3l is deqelrating, and slide 8l is returning to a more remote lefthand position (Fig. 1) the slide projection 82 strikes the spring 23 a t a very great angle. Therefore. the spring 23 tends to obstruct the slide projection 82 from passing until the current is turned off and the spring pressure of the governor overcomes the weaker spring 23.

I have shown the control circuit connected to the control winding through external connections 23 and 21 which pass through insulated bushingsl 4 ditional coacting brushes mounted on slidable tube 4 for selective connectionV therewith. I have shown cable conductor 21 connected through ilexible connection 2lb to the brush I0 in insulated relation to the supporting tubular slide 4.

Where the system of my invention is applied to a motor starter, as schematically represented in Figs. 1 and 5, I may arrange the taps on resistance I6,l as represented in Fig. 5 at 0', 2', 4', 6', 8', I0', I2', I4', I6', I8', and 20'. Tap 0 is connected to a limit stop 28 with which brush I9 may form a contacting abutment when all of the resistance is effectively out of the starter circuit. The taps are graduated to represent resistance in ohms in the starter circuit.

If the motor armature at a standstill were connected directly to the power mains then, since its resistance issmall, a large -current would flow throughl the armature and burn the windings and the brushes. Consequently, a resistance is inserted into the circuit when starting and gradually cut out until the motor is running at normal speed. However, the tendency in the operation of electrical machinery is to make the starters and controllers self-governing so that the machinery cannot be injured by careless or unskilled operators. The starting system herein described is very practical. The mechanism of my invention has the desirable characteristic of automatically returning to the position of high resistance should the circuit be interrupted.

Fig. 6 shows the resistance coll reversed so as to serve as a. constant speed governor. Constant speed governors are necessary to maintain a desired speed, to keep electrical machinery from running away and to keep a constant speed in spite of variable loads. Fig. 7 shows the starter and constant speed governor combined to form a starter-governor combination. This combination can be used where it is desirable to automatically start electrical machinery safely and keep said machinery at a constant speed in spite of variable loads.

The resistance I6 is controlled by variable tap I9 and disposed in the motor or generator circuIt in series with the brushes of armature 28 as generally indicated in Fig. 8.

The taps on resistance I6, in the constant speed governor control system of Fig. 6, are arranged in the reverse order to that illustrated in Fig. 5: that is taps 0", I", 2", 3", 4". 5", 6", 1", 8", 9", and I0" and movement of brush I0 toward the right tends to cut in the eiective resistance.

In the starter governor combination shown ln Fig. 7, the taps are arranged from a low resistance intermediate position along resistance I6 as represented at 29 to a high resistance value progressing on opposite sides thereof, as represented by taps extending to the right of the intermediate point 29 at 2', 4"', 6', 8"', and IU". A similar arrangement of graduated resistance extending from a relatively low value to a relatively high value is arranged on the left of intermediate tap 29 as represented at 2"", 4"", 6"", 8"", I2"". 4MM |611", Ian", and 20H"- In the operation of the control system of my invention the revolving centrifugal governor pulls the non-revolving slide 4 out as the shaft 3I gains speed. Brush I0, mounted on insulated member II, slides along separated contact points I4. Negative lead 21 connects with brush I0. In the case of the starter, the positive lead connects to the right end of the coil. In the case of the constant speed-governor, the positive lead is connectedto the left end of the coil as shown in Fig.

6. As Fig. 7 shows the positive lead is connected to the center oi' the coil in the case of the starter-governor combination. and the resistance increases towards each end.

Fig. 1 shows the coil in cross-section. The insulated resistance wire can be seen wound on the core at i6. At 2', I', 3'20 it can be seen where the resistance wire is tappedA at intervals of equal resistance and connected to contact points i4 which are insulated from each other. Each contact point has the shape of a perfect cube.

'Ihe centrifugal governor has been shown in Fig. 1 in the extended position at starting with the brush lll contacting the resistance coil Ii adjacent the end oi' the greatest resistance.

As the current enters the amature 2l, the motor starts with a minimum amount of current allowed to flow. As the shaft 3| gains speed the centrifugal governor spins outward and the brush l is pulled along vthe contact points of decreased resistance. Therefore. the ilow of current increases as the speed increases. This smooth regulation of current isv not subject to the human error possible in hand starting.

Eventually the brush hits the limit stop 28, the resistance is completely cut out of the circuit and the motor (or generator) is safely running at top speed. When the motor is turned oi'f, the weights 13 and 14 of the centrifugal governor come to rest against the shaft due to spring tension 2l and 22 and the brush is again contacting the coil at theA position of highest resistance ready for starting again.

Fig. 6 shows how, by simply reversing the resistance coil, the apparatus becomes a constant speed governor. 'I'he governor may be adjusted to maintain a constant speed when the brush contacts the resistance at two ohms. Should the motor (or generator) speed up, the brush will slide along to a higher resistance. As current varies inversely with resistance, the more resistance in a circuit the less current will flow. When the motor receives less current, the brush will move down towards two ohms again and settle at a position where a balance is maintained.

If the load on the motor is increased, the motor will slow down, the brush will move towards the zero resistance, the current will increase, the motor will speed up again and tend to create a balance between load and current, thus maintaining nearly constant speed despite variable loads. Spring the constant speed governor.

Fig. 7 shows how, by winding both coils on the one core the mechanism can be used as an automatic starter and a constant speed governor. Instead of two coils, just the starter coil could be used provided double taps were taken from each point on the coil and the two high resistance wires would be tapped at either end of the row of contacts and the lesser resistance wires would progressively b e placed inboard of each of the end taps until the no resistance tap would be placed in the center. When the current is turned on, the brush slides over the resistance coil until all the resistance is cut out of the circuit and.. the motor is safely running at normal speed. It

continues to gain momentum until the system, balances, possibly at four ohms resistance on the governor coil. This condition will be stable until the load is decreased or increased. If the load is decreased, the centrifugal governor will pull the brush up to a higher resistance where it member 231s not used for l will balance and stay constant for that load. Should the load increase, then the brush I0 will Y slide down towards the zero resistance, more current will enter the circuit and the motor will balance possibly around the one ohm resistance where it will remain constant for that load. If, however, for a certain type of machinery, too great a load be added. the brush l0 will slide past the zero resistance and go on to an everincreasing resistance. With the excess load and the diminishing current. the mechanism would have a tendency to stop the motor. Therefore, to combat such a tendency due to slight overload, spring 23 and recesses 2I-2I of Fig. 1 are included in the mechanism only when the starter or starter-governor combination is used.

l Slide 8i and recess 24 is standard in all forms of the switch. But when the starter or combination starter-governor is used, that shaft has the Aextra recess 25 and spring 23 installed. I'he spring 23 slopes, gradually enabling the prolector 82 on slide 8i to easily travel over it when the motor is speeding up. But coming back, the slide hits the spring at a very great angle. Therefore, the spring 23 will prevent the projection 82 on slide 8i from passing until the current is turned oi! and the spring pressure of the governor overcomes -the weaker spring 23. As a result, should the starter-governor combination shown in Fig. 7 become overloaded, the centrifugal governor will slow down and push the brush I0 along the contact points until the zero resistance is arrived at. At this point, the spring 23 will prevent the governor from pushing the brush 23 past the critical point. The slide Il will finally push spring 23 down and slide the brush l0 to the high resistance only when the circuit is interruptedand the governor weights 13 and 14 come down against the shaft 3i.

The constant speed governor and starter-gow ernor combination will maintain a constant speed sleeve member when there is no change in the load. In cases where there is a variable load, the governor will maintain a constant speed after it balances for that particular load. The motor will lose speed when the load is increased. but it will only lose about half the speed that a motor without the governor would lose. This is caused by the fact that the current increases as the load increases, and the current decreases as the load decreases.

Referring to Figs. 9-11, the motor shaft 3|, which extends from the electric motor 21, carries the friction drive wheel 3l for engagement with any mechanism that is to be rotatably driven. The shaft extends through a housing 53 having an anti-friction bearing connection with shaft 3i as represented at B6. The housing I3 thus serves as a dust and moisture-tightvcover for the preision mechanism contained therein.

'Ihe speed governing mechanism includes a 61, secured by set screw Il to a selected position on shaft 3|. The position of sleeve 81 may be adjusted longitudinally of the shaft for increasing or decreas the speed at which the governor mechanism operates to open the series circuit to the driving motor mechanism. Sleeve E1 is provided with pairs of radially projecting lugs represented at and 1l, forming pivot means for arms 1I and 12 which carry centrifugally operated weights 13 and 14 'on the ends thereof. Arms 1l and 12 have lugs 1l and 1l extending inwardly therefrom forming pivotal connections for link members I1 and 1I which pivotally connect with radially extending lugs 1l and SII, carried by longitudlnallyslidable sleeve 7 member 8|. The longitudinally slidable sleeve member 8| has an inwardly projecting key 82 thereon, which is longitudinally slidable in a keyway or slot 83 formed in shaft 3|. As the weights 13 and 14 swing outwardly under centrifugal force due to increased speed of shaft 3| and friction drive wheel 30 in frictional engagement with the rotary member to be driven, a pull is exerted on sleeve 8| displacing sleeve 8| longitudinally of shaft 3|. Sleeve 8| cannot turn relatively to shaft 3| but is only slidable longitudinally with respect thereto. The sleeve 8| has a radially extending flange 84 on the end thereof opposite to the end at which links 11 and 18 pivotally connect. The faces of flange 84 provide slidable connection with collar member 85 through the ball -races indicated at 86 and 81 secured in ball race plates 88 and 89. The collar member 85 has a pair of longitudinally extending arms 90 and 9| with hook-shaped ends 90a and 9|a for engagement with the inwardly extending flange 92 of collar member 93. Collar member 93 has an annular space therein indicated at 93a, within which the hook-shaped ends 90a and 9 la of members 90 and 9| are free to be displaced longitudinally within definite limts. Thus a lost motion connection is provided between collar member 93 and the system of centrifugal weights including weights 13 and 14.

Sleeve member 94 projects from the housing of the motor 21 and terminates shortly beyond the closed circuit position for the governing mechanism and serves as a support and guide for the parts to which the collar assembly 93 is connected. The extremity of the sleeve 94 is grooved at 90b and 9|b to allow the longitudinal movement of the arms 90 and 9| under centrifugal action of the switch control mechanism. Antifrlction bearings 95 and 96 are provided between shaft 3| and sleeve member 94 for maintaining accurate alignment of the parts and reducing friction to a minimum.

The collar assembly 93 has an insulated bushing 91 and a ring member 90v secured thereto by screw members 99. Insulated bushing 91 slidably connects with sleeve member 94 and may be displaced longitudinally thereof. The insulated bushing 91 serves as an insulated support for the annular conductive ring member |00. The securing screws 99 are countersunk in insulated bushing 91 and thus do not electrically connect with ring member |00. The ring member is provided with an inwardly extending flange |00a fitting within an annular groove in insulated bushing 91 for forming a substantial mechanical connection therewith while at the same time maintaining ring member |00 in substantial insulated relation to all parts of the collar assembly 93. There is embedded in insulated bushing 91 an eyelet member |0| in insulated relation to ring member |00, ring member 98 and the other parts of the collar assembly 93. The eyelet |0| provides a connection for coil spring |02 which is secured at the other end |03 to the frame of the motor 21. Coil spring |02 tends to continuously draw the collar assembly 93 toward the motor frame 21 for maintaining the face of conductive annular ring |00 in electrical connection with the contact segments |04 and |05 forming the terminals for the series circuit through conductors 52 and 54 in the series control path explained in Fig. 8. The segments |04 and are insulatingly mounted as represented at |06 and |01 in the extremity of the tubular frame member |08 that projects from the motor frame 21. The conductors 52 and 54 enter opposed sides of housing 53 through insulated bushings |09 and H0 as shown and electrically connect with segments |05 and |04.

Under normal conditions of rotation, coil .spring |02 maintains the annular conductive ring |00 in contact with the segments |04 and |05. However, as the speed increases, the centrifugal weights move outwardly, displacing sleeve 8| longitudinally of the shaft system until a position is reached in which the hook-shaped ends 90a and 9|a vof arms 90 and 9| pull the collar assembly 93 further away from the end of tubular member |08, as represented in Fig. 11, separating the annular conductive ring member |00 from electric circuit connection with segments |04 and |05, thus opening the series circuit path illustrated as closed in the position shown in Fig. 9.

The arrangement of the apparatus of my invention shown in Figs. 1-8 is intended for the control of a circuit variable in association with any rotating electrical apparatus, whereas, in the form of my invention illustrated in Figs. 9-11. I have shown a mechanism for positively interrupting the continuity of an electrical circuit associated with the rotating electrical apparatus. Depending upon the conditions under which the apparatus must operate, one or the other of the alternative arrangements may be very effectively employed.

I realize that various changes may be made in the construction of the components of the c'entrifugal switch system of my invention and, while I have described my-invention in certain of its preferred embodiments, I desire that it be understood that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A centrifugal control switch for electric motors comprising a driven motor shaft, a centrifugal weight system displaceable in proportion to the speed of the motor shaft, a tubular projection concentrically surrounding said motor shaft and forming a guide, a collar member slidable on the guide formed by said tubular projection, connection between said centrifugal weights and said collar member, an electric contact system associated with said collar member, a complementary electric contact system associated with said tubular projection, and spring means for normally maintaining said contact systems in electrical contact for completing an electrical circuit through said contact systems, said centrifugal weights operating under conditions of excessive speed for separating said contact systems and opening the electrical circuit.

2. A centrifugal control switch comprising in combination with a driven shaft, a tubular member surrounding said shaft in spaced relation thereto, a displaceable tube mounted for longitudinal sliding movement on said tubular member, an electrical contactor supported by said displaceable tube, an impedance surrounding said displaceable tube and having a multiplicity of progressively arranged contacts connected with spaced taps therein, said contacts beingengageable by said electrical contactor supported by said displaceable tube, and means fixed to said driven shaft for varying the position of said displaceable tube and electrical contactor carried thereby according to the speed of rotation of said driven shaft.

3. A centrifugal control switch comprising in combination with a driven shaft, a tubular member surrounding said shaft in spaced relation thereto, a displaceable tube mounted for longitudinal sliding movement on said tubular member, an electrical contactor supported by said tube, an impedance surrounding said displaceable tube and having a multiplicity of progressively arranged contacts connected with spaced taps therein, said contacts being engageabie by said electrical contactor supported by said displaceable tube, means fixed to said driven shaft for varying the position of said displaceable tube and electrical contactor carried thereby according to the speed of rotation of said driven shaft, and means associated with said driven shaft for restricting the movement of said displaceable tube and the displacement of said electrical contactor with respect to said progressively arranged contacts.

4. A centrifugal switch comprising in combination with a driven shaft, a tubular housing surrounding said shaft, a frame structure disposed in concentric spacial relation to said tubular housing, a winding carried by said frame structure, progressively disposed taps on said impedance winding, a row of progressively arranged contacts mounted in insulated relation to said frame structure and intermediate said frame structure and said tubular housing, connections progressively arranged between said contacts and the taps on said winding, a slidable electrical contactor movable between said housing and said progressively arranged row of contacts for establishing progressive electrical connection therewith, and means associated with said driven shaft for variably displacing said slidable electrical contactor in accordance with the velocity of rotation of said driven shaft for variably including an effective portion of said impedance winding in an electrical circuit between said electrical contactor and one terminating end of said impedance winding in proportion to the speed of rotation of said driven shaft.

5. A centrifugal switch comprising in combination with a driven shaft, a tubular housing surrounding said shaft in spaced relation thereto, a frame structure disposed in concentric spacial relation to said tubular housing, a winding carried by said frame structure, progressively disposed taps on said impedance winding, a row of progressively arranged contacts mounted in insulated relation to said frame structure and intermediate said frame structure and said housing, connections progressively arranged between said contacts and the taps on said winding, a tubular member slidable on said tubular housing within said frame structure, an electrical contactor mounted on said tubular member and movable between said tubular housing and said progressively arranged rows of contacts for establishing progressive electrical connection therewith, a centrifugally operated mechanism associated with said driven shaft and coupling means between said centrifugally operated mechanism and said tubular member for progressively displacing said electrical contactor with respect to said progressive row of contacts in proportion to the speed of rotation of said driven shaft for effectively including a selected portion of said impedance winding in a series circuit between said electrical contactor and one of the terminating ends of said impedance winding in proportion to the speed of rotation of said driven shaft.

6. A centrifugal switch comprising in combination with a driven shaft, a tubular housing surrounding said shaft in spaced relation thereto, a frame structure disposed in concentric spacial relation to said tubular housing, an impedance winding carried by said frame structure. pro'gressively disposed taps on said impedance winding, a row of progressively arranged contacts mounted in insulated relation to said frame structure and intermediate said frame structure and said housing, connections progressively arranged between said contact and the taps on said impedance winding... tubular member slidable on said tubular housing within said frame structure, an electrical contactor mounted on said tubular member and movable between said tubular housing and said progressively arranged row of contacts for establishing progressive electrical connection therewith, l. centrlfugally operated mechanism associated with said driven shaft, coupling means between said centrifugally operated mechanism and said tubular member for progressively displacing said electrical contactor with respect to said progressive row of contacts in proportion to the speed of rotation of said driven shaft for effectively including a selected portion of said impedance winding in a series circuit between said electrical contactor and one of the terminating ends of said impedance winding in proportion to the speed of rotation of said driven shaft, and spring means associated with said centrifugal means for normally biasing said electrical contactor to a predetermined limiting position with respect to said progressive row of contacts.

7. A centrifugal switch comprising in combination with a driven shaft, a tubular housing surrounding said shaft in spaced relation thereto, a frame'structure disposed in concentric spacial relation to said tubular housing, a winding carried by said frame structure, progressively disposed taps on said impedance winding, a row of progressively arranged contacts mounted in insulated relation to said frame structure and intermediate said frame structure and said housing, connections progressively arranged between said contact and the taps on said impedance winding, a tubular member slidable on said tubular housing within said frame structure, an electrical contactor mounted on said tubular mem ber and movable between said housing and said progressively arranged row of contacts for establishing progressive electrical connection therewith, a centrifugally operated mechanism associated with said driven shaft and anti-friction rotative coupling means between said centrifu gally operated mechanism and said tubular member for progressively displacing said electrical contactor with respect to said progressive row of contacts in proportion to the speed of rotation of said driven shaft for effectively including a selected portion of said impedance winding in a series circuit between said electrical contactor and one of the terminating ends of said impedance winding in proportion to the speed of rotation of said driven shaft, spring means associated with said centrifugal means for normally biasing said electrical contactor to a predetermined limiting position with respect to said progressive row of contacts, and means associated with said driven shaft and engageable with a portion of said anti-friction rotative coupling means for restricting longitudinal displacement of said anti-friction rotative coupling means with respect to said shaft in coaction with the operation of said centrifugal means.

8. A centrifugal control switch comprising in combination with a driven shaft, a tubular member surrounding said shaft in spaced relation thereto, a displaceable tube mounted for longitudinal sliding movement on said tubular member, an electrical contactor supported by said displaceable tube, an annular flange on one end of said displaceable tube, a coupling member slidable on said shaft and having a flange adapted to coact with and extend substantially parallel to the aforesaid ange, means coupling said flanges one to the other while allowing free rotative movement of said last mentioned flange with respect to said rst mentioned flange, an impedance surrounding said displaceable tube and having a multiplicity of progressively a1'- -ranged contacts connected with spaced taps therein, said contacts being engageable by said electrical contactor supported by said displaceable tube, and means fixed to said driven shaft and connected with said coupling member for imparting translatory movement to said coupling member for varying the position of said displaceable tube and the electrical contactor carried thereby according to the speed of rotation of said driven shaft.

9. A centrifugal control switch comprising in combination with a driven shaft, a tubular member surrounding said shaft in spaced relation thereto, a displaceable tube mounted for longitudinal sliding movement on said tubular memberl an electrical contactor supported by said displaceable tube, an annular flange on one end of said displaceable tube, a coupling member slidable on said shaft and having a flange adapted to coact with and extend substantially parallel to the aforesaid ange, means coupling said flanges one to the other while allowing free rotative movement of said last mentioned ange with respect to saidrst mentioned flange, an impedance surrounding said displaceable tube and having a multiplicity of progressively arranged contacts connected with spaced taps therein, said contacts being engageable by said electrical contactor supported by said displaceable tube, means xed to said driven shaft and connected with said coupling member for imparting translatory movement to said coupling member for varying the position of said displaceable tube and the electrical contactor carried thereby according to the speed of rotation of said driven shaft, and means 12 extending between said coupling member and said shaft for limiting the movement of said displaceable tube in opposite directions.

10. A centrifugal control switch comprising in combination with a driven shaft, a tubular member surrounding said shaft in spaced relation thereto, a displaceable tube mounted for longitudinal sliding movement on said tubular member, an electrical contactor supported by said displaceable tube, an annular ange on one end of said displaceable tube, a coupling member slidable on said shaft and having a flange adapted to coact with and extend substantially parallel to the aforesaid flange, a sleeve member having a cylindrical portion connected with said first mentioned flange and embracing said second mentioned flange and terminating in a ilange member extending in spaced parallel relation to said second mentioned flange, ball races interposed between the opposite faces of said second mentioned flange and the face of said first mentioned flange and the face of said ange member, anti-friction bail members disposed in said ball races, an impedance surrounding said displaceable tube and having a multiplicity of progressively arranged contacts connected with spaced taps therein, said contacts being engageable by said electrical contactor supported by said displaceable tube, and means fixed to said driven shaft and connected with said coupling member through said second mentioned ange and the ball race connections thereof with said first mentioned flange and the flange member of said sleeve for imparting translatory movement to said coupling member for varying the position of said displaceable tube and the electrical contactor carried thereby according to the speed of rotation of said driven shaft.

" ROBERT A. FELBURG.

REFERENCES CITED The following references are of record in the le of this patent:'

UNITED STATES PATENTS 

